Underwater navigation device with bionic swimming bladder and motion control algorithm

Abstract

The invention discloses an underwater navigation device with a bionic swimming bladder and a motion control algorithm, the underwater navigation device with the bionic swimming bladder comprises a shell, a first flexible film, a second flexible film, a push-pull rod driving mechanism and a tail fin propelling mechanism, the shell comprises a head part, a tail part and a main body connecting the head part and the tail part, the first flexible film is arranged between the head and the main body, the second flexible film covers the notch of the main body, and the first flexible film, the main body and the second flexible film define a swimming bladder chamber; the volume change of the swimming bladder chamber caused by the deformation of the first flexible film is greater than the volume change of the swimming bladder chamber caused by the deformation of the second flexible film; the push-pull rod driving mechanism is used for driving the first flexible film to deform, and the tail fin propelling mechanism is arranged at the tail; the tail fin driving mechanism is arranged in the shell and used for driving the bionic tail fin to swing. According to the technical scheme provided by the invention, the technical problems of long buoyancy regulation response time and high energy consumption of an underwater navigation device with a bionic swimming bladder can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and particularly to an underwater navigation device with a bionic swim bladder and a motion control algorithm. Background Art

[0002] An underwater navigation device is a device that can navigate autonomously or remotely underwater and perform specific tasks, and is widely used in many fields such as military, marine science, and underwater engineering. However, in order to achieve buoyancy adjustment, underwater navigation devices generally have technical problems of long response time and high energy consumption.

[0003] Therefore, it is necessary to provide a new underwater navigation device with a bionic swim bladder and a motion control algorithm to solve the above technical problems. Summary of the Invention

[0004] The main object of the present invention is to provide an underwater navigation device with a bionic swim bladder and a motion control algorithm, aiming to solve the technical problems of long response time and high energy consumption existing in underwater navigation devices.

[0005] To achieve the above object, an underwater navigation device with a bionic swim bladder proposed by the present invention includes a housing, a first flexible membrane, a second flexible membrane, a push rod driving mechanism, and a tail fin propulsion mechanism. The housing includes a head, a tail, and a main body connecting the head and the tail. The first flexible membrane is disposed between the head and the main body. The main body is provided with a notch, and the second flexible membrane covers the notch. The first flexible membrane, the main body, and the second flexible membrane enclose to form a swim bladder chamber. Definition: The volume change of the swim bladder chamber caused by the deformation of the first flexible membrane is ΔV1, and the volume change of the swim bladder chamber caused by the deformation of the second flexible membrane is ΔV2. Then: |ΔV1| > |ΔV2|;

[0006] The push rod driving mechanism is disposed in the swim bladder chamber and is used to drive the deformation of the first flexible membrane. The tail fin propulsion mechanism includes a bionic tail fin and a tail fin driving mechanism. The bionic tail fin is rotatably disposed at the tail. The tail fin driving mechanism is disposed in the housing and is used to drive the bionic tail fin to swing.

[0007] In an embodiment, the push rod driving mechanism includes a fixed seat, a driving member, and a pushing block. The driving member and the pushing block are both disposed on the fixed seat. The pushing block is connected to the output end of the driving member and abuts against the first flexible membrane. The driving member is used to drive the pushing block to move in a direction close to or away from the head to drive the deformation of the first flexible membrane.

[0008] In one embodiment, the pushing block and the driving member are spaced apart on the fixed seat. The pushing block includes an inner rod and an outer tube arranged coaxially. The inner rod is rotatably arranged on the fixed seat, and the inner rod passes through the outer tube and is threadedly connected to the outer tube. The driving member is used to drive the inner rod to rotate, and further drive the outer tube to move in a direction close to or away from the head.

[0009] In one embodiment, the pushing block is provided with a push head, and the push head is provided with an arc surface that abuts against the first flexible film.

[0010] In one embodiment, both the first flexible film and the second flexible film are embedded with flexible sensors; and the elasticity of the first flexible film is greater than that of the second flexible film; and / or, the area of the first flexible film is larger than that of the second flexible film; and / or, the thickness of the first flexible film is smaller than that of the second flexible film.

[0011] In one embodiment, the caudal fin driving mechanism includes a driving unit connected in sequence, and a shaft rod, a connecting rod and a swing arm hinged in sequence. The bionic caudal fin is rotatably arranged on the tail through a rotating shaft. The shaft rod is connected to the output end of the driving unit. The swing arm is hinged to the rotating shaft, and the swing arm is arranged at an angle with the rotating shaft. The connecting rod is arranged at an angle with the shaft rod and at an angle with the swing arm.

[0012] In one embodiment, the underwater navigation device with a bionic swim bladder further includes a pectoral fin flapping mechanism. The pectoral fin flapping mechanism includes a bionic pectoral fin and a pectoral fin driving mechanism. The pectoral fin driving mechanism is arranged in the housing. The bionic pectoral fin is rotatably arranged on the pectoral fin driving mechanism and extends out of the main body. The pectoral fin driving mechanism is used to drive the bionic pectoral fin to swing around its rotation axis, and is used to drive one end of the bionic pectoral fin away from the main body to rotate in a direction close to or away from the head.

[0013] In one embodiment, the pectoral fin driving mechanism includes a bracket, a first servo motor, a second servo motor and a transmission member arranged on the bracket. The bionic pectoral fin is rotatably arranged on the transmission member. The first servo motor drives the bionic pectoral fin to rotate around the vertical direction of the transmission member through the transmission member, so that one end of the bionic pectoral fin away from the main body rotates in a direction close to or away from the head. The second servo motor drives the bionic pectoral fin to swing around its rotation axis through the transmission member.

[0014] In one embodiment, the transmission member includes a housing and a helical gear disposed within the housing. One end of the bionic pectoral fin is disposed within the housing and meshes with the helical gear. The bracket is further provided with a first synchronous pulley, a second synchronous pulley, and a first shaft body and a second shaft body coaxially nested. The first shaft body connects the first synchronous pulley and the housing, and the second shaft body is connected to the helical gear;

[0015] The first servo motor drives the first shaft body to rotate through a first synchronous belt and the first synchronous pulley, and then drives the housing to rotate around the vertical direction of the transmission member, so as to drive the bionic pectoral fin to rotate around the vertical direction of the transmission member; the second servo motor drives the second shaft body to rotate through a second synchronous belt and the second synchronous pulley, and then drives the helical gear to rotate, so as to drive the bionic pectoral fin to swing around its rotation axis.

[0016] In one embodiment, the underwater navigation device with a bionic swim bladder is further provided with a sensor group, and the sensor group includes a vision sensor, a depth sensor, and an inertial sensor.

[0017] In addition, the present invention also proposes a motion control method, which is applied to the underwater navigation device with a bionic swim bladder as described above. The motion control method includes:

[0018] Obtain the current speed information, current heading information, and current pitch attitude information of the underwater navigation device with a bionic swim bladder;

[0019] Compare the preset speed information with the current speed information, and according to the error value between the preset speed information and the current speed information, control the tail fin drive mechanism to operate by the bionic tail fin controller, and adjust the swimming speed of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset swimming speed;

[0020] Compare the preset heading information with the current heading information, and according to the error value between the preset heading information and the current heading information, control the pectoral fin drive mechanism to operate by the bionic pectoral fin controller, and adjust the heading angle of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset heading angle;

[0021] Compare the preset pitch attitude information with the current pitch attitude information, and according to the error value between the preset pitch attitude signal and the current pitch attitude information, control the push-pull rod drive mechanism to operate by the bionic swim bladder controller, and adjust the pitch attitude and depth of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset pitch attitude and depth.

[0022] The technical solution of the present invention can achieve rapid adjustment of the buoyancy of the underwater navigation device by providing a first flexible film and a second flexible film that enclose to form a swim bladder chamber with the main body, and driving the deformation of the first flexible film through a push rod driving mechanism. At the same time, by adjusting the volume of the swim bladder chamber by the second flexible film through water pressure or gas pressure in the swim bladder chamber, the energy consumption of the underwater navigation device can be reduced. In this embodiment, the first flexible film is arranged between the head and the main body, the second flexible film is arranged on the peripheral wall of the main body, and the first flexible film, the second flexible film and the main body enclose to form a swim bladder chamber. The push rod driving mechanism is arranged in the outer shell and is used to drive the deformation of the first flexible film; by directly driving the deformation of the first flexible film through the push rod driving mechanism, the volume of the underwater navigation device can be changed more quickly, and the buoyancy of the underwater navigation device can be adjusted. It does not need to compress and transmit gas, and can improve the response speed of the underwater navigation device during buoyancy adjustment. The second flexible film arranged on the main body can reduce the energy consumption of the underwater navigation device; specifically, the second flexible film only depends on water pressure or gas pressure in the swim bladder chamber to adjust the volume of the swim bladder chamber, and then changes the volume of the underwater navigation device. It does not need to be provided with additional energy for driving, and can reduce the energy consumption of the underwater navigation device. Moreover, when the push rod driving mechanism drives the deformation of the first flexible film to adjust the buoyancy of the underwater navigation device, the second flexible film can passively compensate for the buoyancy change of the head of the underwater navigation device, so as to avoid the weightlessness of the underwater navigation device and ensure the stability of the underwater navigation device during buoyancy adjustment. The volume change of the swim bladder chamber caused by the deformation of the first flexible film is greater than the volume change of the swim bladder chamber caused by the deformation of the second flexible film. The purpose is to ensure that when the push rod driving mechanism drives the deformation of the first flexible film, the volume of the underwater navigation device can be changed; specifically, when the push rod driving mechanism drives the first flexible film to bulge towards the head, the first flexible film will squeeze out the water in the head, and the second flexible film will be indented inward under the action of water pressure. Since the volume change of the swim bladder chamber caused by the deformation of the first flexible film is greater than the volume change of the swim bladder chamber caused by the deformation of the second flexible film, the volume of the underwater navigation device will gradually increase when the push rod driving mechanism drives the deformation of the first flexible film, which is helpful for the volume expansion and buoyancy increase during the floating process to save the floating energy consumption; on the contrary, the volume of the underwater navigation device will gradually decrease when the push rod drives the deformation of the first flexible film, which is helpful for the volume contraction and buoyancy reduction during the diving process to save the diving energy consumption. The tail fin propulsion mechanism is used to provide propulsion force for the underwater navigation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0024] Figure 1 Schematic structural diagram of an underwater navigation device with a bionic swim bladder in an embodiment provided by the present invention;

[0025] Figure 2 Schematic structural diagram of a push rod driving mechanism in an embodiment provided by the present invention;

[0026] Figure 3 Schematic structural diagram of an underwater navigation device with a bionic swim bladder removing the push rod driving mechanism in an embodiment provided by the present invention;

[0027] Figure 4 Schematic structural diagram of a pectoral fin flapping mechanism in an embodiment provided by the present invention;

[0028] Figure 5 Schematic flow chart of a motion control method in an embodiment provided by the present invention.

[0029] Explanation of the reference numerals in the drawings:

[0030] 100, housing; 110, head; 120, tail; 130, main body; 131, swim bladder chamber; 200, first flexible membrane; 300, second flexible membrane; 400, push rod driving mechanism; 410, fixed seat; 411, sleeve; 420, driving member; 430, pushing block; 431, inner rod; 432, outer tube; 433, push head; 4331, arc surface; 500, tail fin propulsion mechanism; 510, bionic tail fin; 520, tail fin driving mechanism; 521, driving unit; 522, shaft rod; 523, connecting rod; 524, swing arm; 600, pectoral fin flapping mechanism; 610, bionic pectoral fin; 620, pectoral fin driving mechanism; 621, bracket; 6211, first synchronous pulley; 6212, second synchronous pulley; 622, first servo motor; 623, second servo motor; 624, transmission member; 6241, housing; 6242, helical gear.

[0031] The realization of the object, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indications will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, such descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where A and B are satisfied simultaneously.

[0035] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or is unable to be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0036] An underwater navigation device is a device that can navigate autonomously or remotely underwater and perform specific tasks, and it is widely used in many fields such as military, marine science, and underwater engineering. In the actual production and R & D process, researchers found that most underwater navigation devices adjust buoyancy based on the pneumatic principle, that is, by changing the gas volume inside the underwater navigation device to change the buoyancy of the underwater navigation device, thereby achieving floating and diving. It mainly uses an air pump or a similar device to compress and transmit gas to change the gas volume inside the underwater navigation device to achieve buoyancy adjustment. However, when adjusting the buoyancy of the underwater navigation device in the above manner, due to the slow compression and transmission speed of the gas, this will reduce the response speed of the underwater navigation device during buoyancy adjustment. At the same time, both the compression and transmission of the gas require energy, which will increase the energy consumption of the underwater navigation device during buoyancy adjustment.

[0037] The present invention proposes an underwater navigation device with a bionic swim bladder and a motion control algorithm, aiming to solve the technical problems of long response time and high energy consumption existing in the underwater navigation device.

[0038] Please refer to Figure 1, in an embodiment of the present invention, an underwater navigation device with a bionic swim bladder includes a housing 100, a first flexible membrane 200, a second flexible membrane 300, a push-rod driving mechanism 400, and a tail fin propulsion mechanism 500. The housing 100 includes a head 110, a tail 120, and a main body 130 connecting the head 110 and the tail 120. The first flexible membrane 200 is disposed between the head 110 and the main body 130. The main body 130 is provided with a notch, and the second flexible membrane 300 covers the notch. The first flexible membrane 200, the main body 130, and the second flexible membrane 300 enclose to form a swim bladder chamber 131. Definition: The volume change of the swim bladder chamber 131 caused by the deformation of the first flexible membrane 200 is ΔV1, and the volume change of the swim bladder chamber 131 caused by the deformation of the second flexible membrane 300 is ΔV2. Then: |ΔV1| > |ΔV2|. The push-rod driving mechanism 400 is disposed in the swim bladder chamber 131 and is used to drive the deformation of the first flexible membrane 200. The tail fin propulsion mechanism 500 includes a bionic tail fin 510 and a tail fin driving mechanism 520. The bionic tail fin 510 is rotatably disposed at the tail 120. The tail fin driving mechanism 520 is disposed in the housing 100 and is used to drive the bionic tail fin 510 to swing.

[0039] The technical solution of the present invention can realize the rapid adjustment of the buoyancy of the underwater navigation device by providing the first flexible film 200 and the second flexible film 300 that enclose to form the swim bladder chamber 131 with the main body 130, and driving the deformation of the first flexible film 200 through the push rod driving mechanism 400. At the same time, by adjusting the volume of the swim bladder chamber by the second flexible film 300 by means of water pressure or gas pressure in the swim bladder chamber 131, the energy consumption of the underwater navigation device can be reduced. In this embodiment, the first flexible film 200 is disposed between the head 110 and the main body 130, the second flexible film 300 is disposed on the peripheral wall of the main body 130, and the first flexible film 200, the second flexible film 300 and the main body 130 enclose to form the swim bladder chamber 131. The push rod driving mechanism 400 is disposed in the outer shell 100 and is used to drive the deformation of the first flexible film 200; by directly driving the deformation of the first flexible film 200 through the push rod driving mechanism 400, the volume of the underwater navigation device can be changed more quickly, and the buoyancy of the underwater navigation device can be adjusted. It does not need to compress and transmit gas, and can improve the response speed of the underwater navigation device when adjusting the buoyancy. The second flexible film 300 disposed on the main body 130 can reduce the energy consumption of the underwater navigation device; specifically, the second flexible film 300 only relies on water pressure or gas pressure in the swim bladder chamber 131 to adjust the volume of the swim bladder chamber 131, and then changes the volume of the underwater navigation device. It does not need to be provided with additional energy for driving, and can reduce the energy consumption of the underwater navigation device. Moreover, when the push rod driving mechanism 400 drives the deformation of the first flexible film 200 to adjust the buoyancy of the underwater navigation device, the second flexible film 300 can passively compensate for the buoyancy change of the head 110 of the underwater navigation device, so as to avoid the weightlessness of the underwater navigation device and ensure the stability of the underwater navigation device when adjusting the buoyancy. The volume change of the swim bladder chamber 131 caused by the deformation of the first flexible film 200 is greater than the volume change of the swim bladder chamber 131 caused by the deformation of the second flexible film 300. The purpose is to ensure that when the push rod driving mechanism 400 drives the deformation of the first flexible film 200, the volume of the underwater navigation device can be changed; specifically, when the push rod driving mechanism 400 drives the first flexible film 200 to bulge towards the head 110, the first flexible film 200 will push away the water in the head 110, and the second flexible film 300 will be recessed inward under the action of water pressure. Since the volume change of the swim bladder chamber 131 caused by the deformation of the first flexible film 200 is greater than the volume change of the swim bladder chamber 131 caused by the deformation of the second flexible film 300, the volume of the underwater navigation device will gradually increase when the push rod driving mechanism 400 drives the deformation of the first flexible film 200, which is helpful for the volume expansion and buoyancy increase during the floating process to reduce the floating energy consumption; on the contrary, the volume of the underwater navigation device will gradually decrease when the push rod drives the deformation of the first flexible film 200, which is helpful for the volume contraction and buoyancy reduction during the diving process to reduce the diving energy consumption. The tail fin propulsion mechanism 500 is used to provide propulsion force for the underwater navigation device. This underwater navigation device is applied to technical fields such as underwater navigation robots and robotic fish.

[0040] It should be noted that the underwater navigation device with a bionic swim bladder adjusts its buoyancy by changing its own volume through the structural design of the bionic swim bladder, so as to achieve floating and sinking. Specifically, according to Archimedes' derivation formula: F 浮 = ρ 液 gV 排 , when the liquid density and gravitational acceleration remain unchanged, as the volume of the underwater navigation device increases, the buoyancy force received by the underwater navigation device will also increase; on the contrary, as the volume of the underwater navigation device decreases, the volume of water it can displace will also decrease, and the buoyancy force received by the underwater navigation device will also decrease accordingly. Moreover, the first flexible membrane 200 is mainly used in scenarios that require high-precision control, while the second flexible membrane 300 is mainly used in scenarios where the buoyancy does not need to be adjusted frequently, so as to reduce energy consumption. In a specific embodiment, flexible sensors are deployed on both the first flexible membrane 200 and the second flexible membrane 300. Among them, the flexible sensors are embedded in the flexible membrane through stretchable flexible electronic materials to obtain perception data such as the tensile stress and pressure of the first flexible membrane and the second flexible membrane in real time. In this embodiment, the second flexible membrane 300 also helps to generate a pitching moment, so that the underwater navigation device reaches a preset pitching attitude; specifically, when the underwater navigation device needs to be adjusted to a floating attitude, the push rod driving mechanism 400 drives the first flexible membrane 200 to bulge towards the head 110, and the second flexible membrane 300 will contract inward under the action of water pressure, which is more conducive to converting the shape change of the swim bladder chamber 131 into a pitching moment, so that the underwater navigation device reaches a preset pitching attitude. In addition, it should also be noted that in this embodiment, since the center of gravity is located between the first flexible membrane and the second flexible membrane, the active adjustment of the first flexible membrane and the anti-phase stretching of the second flexible membrane can generate pitching moments in the same direction, which is beneficial to generating an upward pitching attitude and floating when the first flexible membrane is pushed out, and generating a downward pitching attitude and diving when the first flexible membrane is retracted.

[0041] Please refer to Figure 2 , in an embodiment of the present invention, the push rod driving mechanism 400 includes a fixed seat 410, a driving member 420, and a pushing block 430. The driving member 420 and the pushing block 430 are both arranged on the fixed seat 410. The pushing block 430 is connected to the output end of the driving member 420 and abuts against the first flexible membrane 200; the driving member 420 is used to drive the pushing block 430 to move towards or away from the head 110, so as to drive the first flexible membrane 200 to deform. In this embodiment, by using the driving member 420 to drive the pushing block 430 to move towards or away from the head 110 to drive the first flexible membrane 200 to deform, the structure of the underwater navigation device can be simplified, and the manufacturing difficulty of the underwater navigation device can be reduced. In a specific embodiment, the driving member 420 can be a driving motor.

[0042] Please refer toFigure 2 In an embodiment of the present invention, the pushing block 430 and the driving member 420 are spaced apart on the fixed seat 410. The pushing block 430 includes an inner rod 431 and an outer tube 432 arranged coaxially. The inner rod 431 is rotatably arranged on the fixed seat 410, and the inner rod 431 passes through the outer tube 432 and is threadedly connected to the outer tube 432. The driving member 420 is used to drive the inner rod 431 to rotate, and further drive the outer tube 432 to move in a direction close to or away from the head 110. In this embodiment, by designing the pushing block 430 as a nested structure composed of the inner rod 431 and the outer tube 432, the distance of the pushing block 430 moving in a direction close to or away from the head 110 can be increased, so as to improve the space utilization rate of the underwater navigation device and make the structure of the underwater navigation mechanism more compact. Specifically, the driving member 420 drives the inner rod 431 to rotate through the cooperation of a synchronous pulley and a synchronous belt, and further drives the outer tube 432 to move in a direction close to or away from the head 110. In a specific embodiment, a sleeve 411 is provided on the fixed seat 410, and the outer tube 432 is slidably passed through the sleeve 411. By slidably passing the outer tube 432 through the sleeve 411, guidance can be provided for the movement of the outer tube 432 to ensure the stability and accuracy of the outer tube 432 moving in a direction close to or away from the head 110. And, to ensure that the rotation of the inner rod 431 can be converted into the linear motion of the outer tube 432, it is necessary to prevent the outer tube 432 from rotating together with the inner rod 431. Specifically, the following structure can be adopted. The sleeve 411 and the outer tube 432 are provided with a matching limiting block and a limiting groove extending along the central axis direction of the outer tube 432, and the limiting block is slidably arranged in the limiting groove.

[0043] Please refer to Figure 2 In an embodiment of the present invention, the pushing block 430 is provided with a push head 433, and the push head 433 is provided with an arc surface 4331 that abuts against the first flexible film 200. In this embodiment, by providing the push head 433 on the pushing block 430 and using the arc surface 4331 of the push head 433 to abut against the first flexible film 200, the first flexible film 200 can be better protected to avoid damage to the first flexible film 200 when it deforms. In a specific embodiment, the push head 433 can be an arc-shaped plate.

[0044] In an embodiment of the present invention, the elasticity of the first flexible film 200 is greater than that of the second flexible film 300; and / or, the area of the first flexible film 200 is greater than that of the second flexible film 300; and / or, the thickness of the first flexible film 200 is less than that of the second flexible film 300. In this embodiment, by making the elasticity of the first flexible film 200 greater than that of the second flexible film 300, the area of the first flexible film 200 greater than that of the second flexible film 300, and the thickness of the first flexible film 200 less than that of the second flexible film 300, it can be ensured that the volume change of the swim bladder 131 caused by the deformation of the first flexible film 200 is greater than the volume change of the swim bladder 131 caused by the deformation of the second flexible film 300. Furthermore, when the push rod driving mechanism 400 drives the first flexible film 200 to deform, the volume of the underwater vehicle can be changed.

[0045] Please refer to Figure 3 , in an embodiment of the present invention, the caudal fin driving mechanism 520 includes a driving unit 521 connected in sequence, and a shaft rod 522, a connecting rod 523 and a swing arm 524 hinged in sequence. The bionic caudal fin 510 is rotatably arranged on the tail 120 through a rotating shaft. The shaft rod 522 is connected to the output end of the driving unit 521. The swing arm 524 is hinged to the rotating shaft, and the swing arm 524 is arranged at an angle with the rotating shaft. The connecting rod 523 is arranged at an angle with the shaft rod 522 and at an angle with the swing arm 524. Specifically, the driving unit 521 is used to drive the shaft rod 522 to rotate, and then drive the connecting rod 523 to rotate around the central axis of the shaft rod 522, and drive the swing arm 524 to rotate around the central axis of the shaft rod 522, so that the end of the swing arm 524 away from the rotating shaft makes a circular motion in the vertical plane, and then drive the rotating shaft to rotate reciprocally, driving the bionic caudal fin 510 to swing reciprocally, providing the propulsion force required for the forward movement of the underwater vehicle.

[0046] Please refer to Figure 4, in an embodiment of the present invention, the underwater navigation device with a bionic swim bladder further includes a pectoral fin flapping mechanism 600. The pectoral fin flapping mechanism 600 includes a bionic pectoral fin 610 and a pectoral fin driving mechanism 620. The pectoral fin driving mechanism 620 is disposed within the housing 100, and the bionic pectoral fin 610 is rotatably disposed on the pectoral fin driving mechanism 620 and extends out of the main body 130; the pectoral fin driving mechanism 620 is configured to drive the bionic pectoral fin 610 to swing about its rotation axis, and is configured to drive the end of the bionic pectoral fin 610 away from the main body 130 to rotate in a direction closer to or farther from the head 110. In this embodiment, by driving the bionic pectoral fin 610 to move through the pectoral fin driving mechanism 620, a bionic flapping motion with two rotational degrees of freedom can be achieved, so as to improve the maneuverability of the underwater navigation device during underwater movement. Specifically, the pectoral fin driving mechanism 620 can drive the bionic pectoral fin 610 to swing about its rotation axis, realizing the pitching motion of the bionic pectoral fin 610 to imitate the up-and-down swing of the pectoral fin of a fish; at the same time, the pectoral fin driving mechanism 620 can also drive the end of the bionic pectoral fin 610 away from the main body 130 to move in a direction closer to or farther from the head 110, realizing the torsional motion of the bionic pectoral fin 610 to imitate the forward-and-backward swing of the pectoral fin of a fish. Moreover, by integrating the motions of the bionic caudal fin 510 and the bionic pectoral fin 610 to obtain an adjustable-amplitude swing of the bionic caudal fin 510 and a two-degree-of-freedom flapping of the bionic pectoral fin 610, the underwater navigation device can be provided with a high-speed and high-maneuverability propulsion ability.

[0047] Please refer to Figure 4 , in an embodiment of the present invention, the pectoral fin driving mechanism 620 includes a bracket 621, a first servo motor 622, a second servo motor 623 and a transmission member 624 disposed on the bracket 621. The bionic pectoral fin 610 is rotatably disposed on the transmission member 624; the first servo motor 622 drives the bionic pectoral fin 610 to rotate about the vertical direction of the transmission member 624 through the transmission member 624, so that the end of the bionic pectoral fin 610 away from the main body 130 rotates in a direction closer to or farther from the head 110, and the second servo motor 623 drives the bionic pectoral fin 610 to swing about its rotation axis through the transmission member 624. Wherein, the vertical direction of the transmission member 624 is as shown by Z in Figure 4 , and the rotation axis of the bionic pectoral fin 610 is as shown by Y in Figure 4 . In this embodiment, two servo motors are used to respectively drive the swing of the bionic pectoral fin 610 about its rotation axis and the rotation about the vertical direction of the transmission member 624, which can avoid the interference caused by the multi-directional rotation of the bionic pectoral fin 610 to ensure the accuracy of the motion of the bionic pectoral fin 610.

[0048] Please refer to Figure 4, in an embodiment of the present invention, the transmission member 624 includes a housing 6241 and a helical gear 6242 disposed within the housing 6241. One end of the bionic pectoral fin 610 is disposed within the housing 6241 and meshes with the helical gear 6242. The bracket 621 is further provided with a first synchronous pulley 6211, a second synchronous pulley 6212, and a first shaft body and a second shaft body coaxially nested. The first shaft body connects the first synchronous pulley 6211 and the housing 6241, and the second shaft body is connected to the helical gear 6242. The first servo 622 drives the first shaft body to rotate through the first synchronous belt and the first synchronous pulley 6211, and further drives the housing 6241 to rotate about the vertical direction of the transmission member 624, so as to drive the bionic pectoral fin 610 to rotate about the vertical direction of the transmission member 624. The second servo 623 drives the second shaft body to rotate through the second synchronous belt and the second synchronous pulley 6212, and further drives the helical gear 6242 to rotate, so as to drive the bionic pectoral fin 610 to swing about its rotation axis. The underwater navigation device with a bionic swim bladder realizes the rotation of the bionic pectoral fin 610 about the vertical direction of the transmission shaft and the swing about its rotation axis by adopting a coaxial nested structural design and a coupling design of the helical gear 6242, and using independent servos, that is, enabling the bionic pectoral fin 610 to imitate the up-and-down swing and forward-and-backward swing of the fish pectoral fin. It can simplify the structure of the underwater navigation device, reduce the structural complexity, and make the structure of the underwater navigation device more compact. At the same time, it can also avoid the interference caused by the multi-directional rotation of the bionic pectoral fin 610 and ensure the accuracy of the movement of the bionic pectoral fin 610. In this embodiment, the two rotational degrees of freedom of the transmission member 624 are conjugate relationships, and the rotation angles of the two servos are the same as the inclination angles of the fin surface of the bionic pectoral fin 610 along the two conjugate axes.

[0049] In an embodiment of the present invention, the underwater navigation device with a bionic swim bladder is further provided with a sensor group, and the sensor group includes a vision sensor, a depth sensor, and an inertial sensor. In this embodiment, the vision sensor is used to capture a wide range of visual information to provide a panoramic image of the underwater environment for the underwater navigation device, help the underwater navigation device identify surrounding obstacles, terrain, and other objects, so as to achieve autonomous obstacle avoidance. The depth sensor is used to measure the depth of the underwater navigation device in the water. The inertial sensor can, on the one hand, measure the pitch angle and yaw angle of the underwater navigation device in real time, and on the other hand, obtain motion state information such as the speed and acceleration of the underwater navigation device.

[0050] In addition, when integrating the first flexible membrane 200, the second flexible membrane 300, and the push-pull rod drive mechanism 400 in the underwater navigation device, three design principles, namely gravity-buoyancy balance, pitch attitude balance, and negative pressure in the swim bladder 131, need to be satisfied. Specifically, regarding the distribution of gravity and buoyancy, when the pushing block 430 of the push-pull rod drive mechanism 400 is in the middle position, by adjusting the overall size and mass of the underwater navigation device, neutral buoyancy is achieved; and by adjusting the spatial layout of the push-pull rod drive mechanism 400, the tail fin propulsion mechanism 500, and the pectoral fin propulsion mechanism 600 in the swim bladder 131, the initial moment of inertia is adjusted so that the lever arm generated by the change in buoyancy of the underwater navigation device is as long as possible, thereby maximizing the regulation effect of the push-pull rod drive mechanism 400. Regarding the air pressure in the swim bladder 131, when the pushing block 430 of the push-pull rod drive mechanism 400 is fully retracted, the air pressure inside and outside the cabin is designed to be equal, so that the swim bladder 131 is in a negative pressure state at any position of the pushing block 430, so that the second flexible membrane 300 is in an anti-phase with the first flexible membrane 200 under the action of water pressure, satisfying the principle of negative pressure inside the cabin.

[0051] Please refer to Figure 5 , Figure 5 which is a schematic flow diagram of the motion control method provided by the present invention. The present invention also proposes a motion control method applied to the above-mentioned underwater navigation device with a bionic swim bladder. The motion control method includes:

[0052] S100. Obtain the current speed information, current heading information, and current pitch attitude information of the underwater navigation device with a bionic swim bladder;

[0053] S200. Compare the preset speed information with the current speed information. According to the error value between the preset speed information and the current speed information, the bionic tail fin controller controls the operation of the tail fin drive mechanism 520 to adjust the swimming speed of the underwater navigation device with a bionic swim bladder so that the underwater navigation device with a bionic swim bladder reaches the preset swimming speed;

[0054] S300. Compare the preset heading information with the current heading information. According to the error value between the preset heading information and the current heading information, the bionic pectoral fin controller controls the operation of the pectoral fin drive mechanism 620 to adjust the heading angle of the underwater navigation device with a bionic swim bladder so that the underwater navigation device with a bionic swim bladder reaches the preset heading angle;

[0055] S400. Compare the preset pitch attitude information with the current pitch attitude information. According to the error value between the preset pitch attitude information and the current pitch attitude information, the bionic swim bladder controller controls the operation of the push-pull rod drive mechanism 400 to adjust the pitch attitude and depth of the underwater navigation device with a bionic swim bladder so that the underwater navigation device with a bionic swim bladder reaches the preset pitch attitude and depth.

[0056] In this embodiment, the motion control method enables the underwater vehicle to reach a preset swimming speed and attitude through feedback control. Specifically, when the underwater vehicle is moving, first, the current speed information, current heading information, and current pitch attitude information of the underwater vehicle are obtained; subsequently, the preset speed information and the current speed information are compared, and according to the error value between the two, the bionic tail fin controller uses a proportional-derivative control algorithm to control the operation of the tail fin drive mechanism 520, adjust the swimming speed of the underwater vehicle, and thus enable the underwater vehicle to reach the preset swimming speed; the preset heading information and the current heading information are compared, and according to the error value between the two, the bionic pectoral fin controller uses a proportional-derivative control algorithm to control the pectoral fin drive mechanism 620, adjust the swing angle of the bionic pectoral fin 610 around its rotation axis and the rotation angle around the vertical direction of the transmission member 624, and thus enable the underwater vehicle to reach the preset heading angle; the preset pitch attitude information and the current pitch attitude information are compared, and according to the error value between the two, the bionic swim bladder controller uses a model predictive control method to control the operation of the push rod drive mechanism 400, and by adjusting the position of the push block 430, adjust the pitch attitude and depth of the underwater vehicle, so that the underwater vehicle reaches the preset pitch attitude and depth. Among them, the proportional-derivative control algorithm is a control algorithm that adjusts the control quantity based on the error signal and its rate of change (derivative). In a specific embodiment, the proportional-derivative control algorithm can be a PD control algorithm. The model predictive control method is based on the swim bladder regulation model in the dynamic model. The current speed information, current heading information, and current pitch attitude information of the underwater vehicle are obtained through the high-frequency sensors or observation sensors in the sensor group.

[0057] The above description is only an exemplary embodiment of the present invention and does not limit the protection scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields, is included in the protection scope of the present invention.

Claims

1. An underwater navigation device with a bionic swim bladder, characterized in that, It includes a housing, a first flexible membrane, a second flexible membrane, a push rod driving mechanism, and a caudal fin propulsion mechanism. The housing includes a head, a tail, and a main body connecting the head and the tail. The first flexible membrane is disposed between the head and the main body. The main body is provided with a notch, and the second flexible membrane covers the notch. The first flexible membrane, the main body, and the second flexible membrane enclose to form a swim bladder chamber. Definition: The volume change of the swim bladder chamber caused by the deformation of the first flexible membrane is ΔV1, and the volume change of the swim bladder chamber caused by the deformation of the second flexible membrane is ΔV2. Then: |ΔV1| > |ΔV2|. The push rod driving mechanism is disposed in the swim bladder chamber and is used to drive the deformation of the first flexible membrane. The caudal fin propulsion mechanism includes a biomimetic caudal fin and a caudal fin driving mechanism. The biomimetic caudal fin is rotatably disposed at the tail. The caudal fin driving mechanism is disposed in the housing and is used to drive the biomimetic caudal fin to swing.

2. The underwater navigation device with a bionic swim bladder as described in claim 1, characterized in that, The push rod driving mechanism includes a fixed seat, a driving member, and a push block. The driving member and the push block are both disposed on the fixed seat. The push block is connected to the output end of the driving member and abuts against the first flexible membrane. The driving member is used to drive the push block to move in a direction close to or away from the head to drive the deformation of the first flexible membrane.

3. The underwater navigation device with a bionic swim bladder according to claim 2, characterized in that, The push block and the driving member are spaced apart on the fixed seat. The push block includes an inner rod and an outer tube arranged coaxially. The inner rod is rotatably disposed on the fixed seat, and the inner rod passes through the outer tube and is threadedly connected to the outer tube. The driving member is used to drive the inner rod to rotate, and further drive the outer tube to move in a direction close to or away from the head.

4. The underwater navigation device with a bionic swim bladder as claimed in claim 2, wherein, The push block is provided with a push head, and the push head is provided with an arc surface abutting against the first flexible membrane.

5. The underwater navigation device with a bionic swim bladder according to claim 1, characterized in that, Both the first flexible membrane and the second flexible membrane are embedded with flexible sensors; and the elasticity of the first flexible membrane is greater than that of the second flexible membrane; and / or, the area of the first flexible membrane is greater than that of the second flexible membrane; and / or, the thickness of the first flexible membrane is less than that of the second flexible membrane.

6. The underwater navigation device with a bionic swim bladder according to claim 1, characterized in that, The caudal fin driving mechanism includes a driving unit connected in sequence, and a shaft rod, a connecting rod, and a swing arm hinged in sequence. The biomimetic caudal fin is rotatably disposed at the tail through a rotating shaft. The shaft rod is connected to the output end of the driving unit. The swing arm is hinged to the rotating shaft, and the swing arm is arranged at an angle with the rotating shaft. The connecting rod is arranged at an angle with the shaft rod and at an angle with the swing arm.

7. The underwater navigation device with a bionic swim bladder as claimed in claim 1, characterized in that, The underwater navigation device with a bionic swim bladder further includes a pectoral fin flapping mechanism, which includes a bionic pectoral fin and a pectoral fin driving mechanism. The pectoral fin driving mechanism is arranged inside the housing. The pectoral fin driving mechanism includes a bracket, a first servo motor, a second servo motor and a transmission member arranged on the bracket. The bionic pectoral fin is rotatably arranged on the transmission member. The first servo motor drives the bionic pectoral fin to rotate around the vertical direction of the transmission member through the transmission member, so that one end of the bionic pectoral fin away from the main body rotates towards or away from the head direction, and the second servo motor drives the bionic pectoral fin to swing around its rotation axis through the transmission member.

8. The underwater navigation device with a bionic swim bladder according to claim 7, characterized in that, The transmission member includes a housing and a helical gear arranged inside the housing. One end of the bionic pectoral fin is arranged inside the housing and meshes with the helical gear. A first synchronous pulley, a second synchronous pulley, and a first shaft body and a second shaft body coaxially nested are further arranged on the bracket. The first shaft body connects the first synchronous pulley and the housing, and the second shaft body is connected to the helical gear; The first servo motor drives the first shaft body to rotate through a first synchronous belt and the first synchronous pulley, and then drives the housing to rotate around the vertical direction of the transmission member, so as to drive the bionic pectoral fin to rotate around the vertical direction of the transmission member; the second servo motor drives the second shaft body to rotate through a second synchronous belt and the second synchronous pulley, and then drives the helical gear to rotate, so as to drive the bionic pectoral fin to swing around its rotation axis.

9. The underwater navigation device with a bionic swim bladder according to any one of claims 1 to 8, characterized in that, The underwater navigation device with a bionic swim bladder is further provided with a sensor group, and the sensor group includes a vision sensor, a depth sensor and an inertial sensor.

10. A motion control method, applied to an underwater navigation device with a bionic swim bladder as described in any one of claims 1 to 9, characterized in that, The motion control method includes: Obtaining the current speed information, current heading information and current pitch attitude information of the underwater navigation device with a bionic swim bladder; Comparing the preset speed information with the current speed information, and according to the error value between the preset speed information and the current speed information, controlling the operation of the tail fin driving mechanism by the bionic tail fin controller to adjust the swimming speed of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset swimming speed; Comparing the preset heading information with the current heading information, and according to the error value between the preset heading information and the current heading information, controlling the operation of the pectoral fin driving mechanism by the bionic pectoral fin controller to adjust the heading angle of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset heading angle; Comparing the preset pitch attitude information with the current pitch attitude information, and according to the error value between the preset pitch attitude information and the current pitch attitude information, controlling the operation of the push rod driving mechanism by the bionic swim bladder controller to adjust the pitch attitude and depth of the underwater navigation device with a bionic swim bladder, so that the underwater navigation device with a bionic swim bladder reaches the preset pitch attitude and depth.

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